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- https://ask.libreoffice.org/en/question/68775/change-default-resolution-in-batch-png-conversion/ gives a first hint about the syntax of that parameters:
"png:writer_png_Export:resolution=300" in a similar example - https://listarchives.libreoffice.org/global/users/msg45846.html indicates that there are some output filter options, and indeed the magic string for the pdf output seems to be "writer_pdf_Export"
- https://listarchives.libreoffice.org/global/users/msg45848.html and https://bugs.documentfoundation.org/show_bug.cgi?id=36313#c17 indicate that the pdf exporter has a lot of undocumented options, the hint is "read the LibreOffice source code"
- Hier befindet sich eine Liste von Optionen: https://wiki.openoffice.org/wiki/API/Tutorials/PDF_export#Links
- ExportLinksRelativeFsys unter Links dürfte die gesuchte sein
- Die Option steht (bei mir) in /usr/lib/libreoffice/share/registry/main.xcd, im Knoten component/Filter/PDF/Export